Re: st: -cluster kmeans- with -weight- or -svyset-

On Sat, Feb 18 2012, David Cefskimal wrote:
> I am using the -cluster kmeans- command to look for opinion clusters
[...]
> kmeans- command. How to change the code including the weighting
> variable w1?
As far as I know, Stata can't deal with weights in any cluster
procedure. In fact, though it seems possible to write code to take
account of weights[1] (for those algorithms where it would matter), I don't
think there are any commonly available implementations.
If your weighting variable has a large range, this may be a problem
(i.e., if some cases have many times the weight of others). If I
understand k-means correctly, weighting would affect the centroid of
each cluster and therefore the solution.
On the other hand, cluster analysis is mainly a descriptive and
exploratory device, and therefore the importance of weighting may be
less (depending on the analyst's concerns).
Regards,
Brendan
[1] Margareta Ackerman, Shai Ben-David, Simina Branzei, David Loker (2011)
`Weighted Clustering', Arxiv:1109.1844
--
Brendan Halpin, Department of Sociology, University of Limerick, Ireland
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